Transducer



Nov. 20, 1956 D. J. MUNROE 2,771,512

TRANSDUCER Filed May 12,1951

Q 2 Sheets-Sheet 2 United States Patent TRANSDUCER David J. Munroe, Racine, Wis., assignor to Webster Electric Company, Racine, Wis., a corporation of Delaware Application May 12, 1951, Serial No. 225,988 8, Claims. (Cl. 179-10041) The present invention relates to transducers and has for its primary object a provision of a new and improved transducer, or pick-up cartridge, as certain devices of this character are sometimes called.

It is an object of the present invention to provide a new and improved multiple stylus transducer. I

A further object of the present invention is to provide a new and improved multiple stylus transducer that is sim ple in construction, small and compact, and readily and simply operable selectively to position the desired stylus into position where it will cooperate with a record.

Another object of the present invention is to provide a new and improved multiple stylus transducer wherein the styli and associated transducer element are mounted in a rotatable part, which part can be rotated in either direction and as many times as desired, and wherein the desired stylus is readily located in correct position for cooperation with a record.

in brief, the transducer of the present invention comprises a housing including two relatively rotatable parts. One of these parts includes terminals adapted electrically to be connected to the transducer element and by means of which the transducer is detach-ably secured to an associated player arm. The other part is rotatable relatively to the first and includes the transducer element, the styli, and a knob-like portion adapted readily to be grasped by the user whereby that portion can be rotated. The rotatable part alsoincludes contact means connected to the transducer and cooperatively associated with the terminals in the relatively fixed part. The contacts in the relatively rotatable part are so constructed so as to cooperate with the terminals in properly locating the rotatable part with the desired stylus in position to cooperate with a record. In order to facilitate this, the relatively rotatable parts are also arranged for some longitudinal relative movement. The rotatable part is constructed of parts fixedly secured together and one of which is the above referred to knob-like part. Also two of the parts constitute a substantially closed housing for the transducer element and, according to one form of construction, they support bearings or trunnions for a stylus carrying shaft or spindle.

Other objects and advantages of the present invention will become apparent from the ensuing description of illustrative embodiments of the invention, in the course of which reference is had to the accompanying drawings, in which Fig. 1 is a top plan view, partly in section, of 'a transducer constructed in accordance with the present invention;

Fig. 2 is a fragmentary side elevational view of the same;

Fig. 3 is a longitudinal cross sectional view taken along the line 3-3 of Fig. 2;

Fig. 4 is a fragmentary cross sectional view taken along the line 4-4 of Fig. 3;

Fig. 5 is an enlarged fragmentary cross sectional view taken along the line 5-5 of Fig. 3;

Fig. 6 is an enlarged transverse cross sectional view taken along the line 6-6 of Fig. 4; v

Fig. 7 is an enlarged perspective view of a:portion of the transducer housing;

Fig. 8 is a fragmentary the line 8-8 of Fig. 4;

Fig. 9 is a transverse cross sectional view taken along the line 9-9 of Fig. 3; also along line 99 of .Fig. 10.

Fig. 10 is a view similar to Fig. 3 of another embodiment of the invention;

Fig. 11 is a transverse cross sectional view taken along the line 11-11 of Fig. 10; and

Fig. 12 is a transverse cross sectional view along the ine 12-12 of Fig. 10.

Referring now to the drawings, and particularly to Figs. 1 and 2, it will be noted that the transducer of the present invention is indicated as a whole by reference character 10. It comprises a multi-part housing 12 cornprising the relatively rotatable parts 14 and 16 of which the former is adapted to be fixedly held and of which the latter is adapted to be rotated. To facilitate rotation, the housing part 16 is provided with an enlarged outer end 18, which is generally knob-like in construction so that it can be readily grasped in the fingers of one hand. The part 13 thus constitutes, in effect, a sort of a knob and to facilitate movement thereof it is provided with a series of longitudinally extending ribs 20.

The transducer of the present invention is illustrated as being a phonograph pick-up cartridge of the multiple stylus type. It includes a pair of substantially diametrically oppositely located styli 22 and 24. The stylus 22 may, for example, be utilized in playing microgroove records. The styli are secured to shanks 26 adapted detachably to be mounted in a chuck 28 mounted in the forward and free end of a transducer element 30 which may be a piezoelectric crystal. The element is mounted within an envelope 32 of rubber or the like secured within a chamber 34 in the housing portion 16 and between inwardly extending portions 36, as disclosed and claimed in the copending application of Clarence F. Jensen, Serial No. 99,086 filed June 14, 1949. A small rubber or other abutment 3'7 can be located centrally between the chuck 28 and end of cap 18 to provide a more stable mounting for the transducer element assembly. Leading from the crystal are a pair of output conductors 38 and 40 which are operatively connected to the transducer prong type terminals 42 and 44 in a manner to be described hereinafter.

The knob-like portion 18 of the housing is a separate structural element secured, as by cement, to the remainder of the housing. The housing 16 is provided with a pair of reduced diameter outer extensions 46 adapted to receive the inner counterbored end 48 of the knob, as best illustrated in Fig. 3 (see also Fig. 12), whereby the two parts can easily be cemented. The knob is provided with opposed openings 54} through which the needle shanks 26 project and the outer surface of the knob is provided with opposed longitudinally extending recesses 52 which protectively receive the styli so that only the needle defining ends protrude beyond the housing. The housing 16 is provided at its inner end with a cap 54 which is also nonrotatably secured, as by cementing, to the housing 16. The inner end of the housing is provided with a counterbore 56 adapted to receive the reduced diameter outer end 58 of the cap 54. In order additionally to insure that the two parts remain in fixed angular relationship they are provided with interengaging structure illustrated as a triangular longitudinal rib 60 on the housing and a V- shaped recess 62 on the cap, see particularly Figs. 3 and 5.

The relatively fixed part 14 of the housing is rotatably secured to the housing 16 as in a counterbore 64 at the inner end of the cap 54. The two are mounted rotatably cross sectional view takenalong relative to each other but in a manner permitting some longitudinal or axial relative movement by means including an elongated eyelet 66 extending through axial openings 68 and 70 in the cap 54 and transducer part 14. The eyelet is relatively fixedly secured to the cap 54 but the opening 70 in part 14 is dimensioned to permit axial movement between the cap and the part 14 of the transducer. The parts are, however, resiliently forced together as by a spring 72 encircling the eyelet and having one end abutting against the bottom of a counterbore 74 in part 14 and the other end abutting against the eyelet.

The prong type terminals 42 and 44, in accordance with one of the features of the present invention, are utilized properly to locate the selected stylus in proper cooperative relation with a record, to make the necessary electrical connnections to the transducer element in the selected position, and the arrangement is further such that the stylus carrying part 16 can be rotated in either direc tion and as far as desired without fear of damaging the transducer or obtaining improper connections.

The terminals 42 and 44 are mounted in diametrically opposed relation in the relatively stationary housing part 14, as in the openings 76 extending therethrough. The prongs are fixedly held in place with the outer ends 42c and 44e projecting a short distance through the part for the purpose of making electrical contact and mechanically positioning the two relatively rotatable parts of the housing. The terminals can be secured either by press fit or cementing or the like.

The electrical contact and positioning means include not only the terminals 42 and 44 but cooperating contact and positioning means in the form of generally U- shaped contacts 80 mounted at diametrically opposite points in the closure cap 54 as best illustrated in Figs. 4, 7 and 8. The bights of the contacts 80 are provided with generally V-shaped indentations 82 providing efficient contact as well as detent type positioning means cooperating with the terminals 44. The contacts 80 are mounted in the end portion of the cap 54 and extend through the reduced diameter portion 58 where the projecting leg portions are bent over as indicated by reference character 84 to provide lugs to which the conductors 38 and 40 can be readily secured as by soldering.

The transducer of the present invention lends itself to construction from plastic materials, as by molding. If a molding process is used the contacts 80 can readily be molded into the end cap 54 before the latter is secured to the portion 16 of the housing. The housing portion 16 can also be molded as a single piece but if desired it can be made as from a tubular piece within which are mounted generally semi-circular inner portions which together provide the housing 34 and the inwardly extending portions 36.

The transducer housing of the present invention can also effectively be used with transducers in which the needles are mounted in chucks secured to a shaft or spindle mounted in spaced apart hearings or trunnions and coupled to a transducer element. A construction of this character is illustrated in Figs. and 11 to which reference is now had.

The transducer housing in Fig. 10 is generally like that already described. However, separate needle chucks 90 are used. These are secured to a spindle or shaft 92 in diametrically opposed relation. The shaft is mounted for limited movement about a longitudinal axis in a pair of spaced apart trunnions or bearings 94 and 100 of rubber or rubber-like material. The bearing 94 is of circular configuration and conveniently mounted in a counterbore 96 in the knob-like front end portion 18 of thetransducer. Beyond the counterbore 96 is a second smaller counterbore 98 to provide clearance for the end of the shaft 92. The other bearing 100 is best illustrated in Fig. 12 from which it can be noted that the bearing consists of two parts 100a encircling the inner end of the shaft 92 and mounted in a recess 102 constituting in effect a continuation of chamber 34.

The shaft 92 is coupled in conventional manner to the outer free end of the transducer element 30 by suitable coupling means 104 so that movements of the shaft result in twisting of the transducer element.

From the above detailed description it may be noted that the transducer of the present invention may be constructed readily and economically and that it provides a light yet rugged transducer. The construction is also such that the desired stylus may be located in cooperative relation to a record in a very simple manner. Assuming that the transducer is mounted in a player or tone arm by means of the prong contacts 42 and 44, then the housing portion part 16 can readily be rotated in either direction, and as far as desired, through the knob portion 18. The accurate positioning of the desired stylus is insured by the detent-contact means including the ends of the prong terminals and the V-shaped grooves 82 in the bight of the contacts 80.

While the present invention has been described in connection with the details of an illustrative embodiment of the invention, it should be understood that these details are not intended to be limitative of the invention except insofar as set forth in the accompaning claims.

What is claimed as new and desired to be secured by Letters Patent of the United States is:

l. A multiple stylus transducer including a pair of relatively rotatable parts, a transducer element and contacts connected to said element on one of said parts, said contacts having outwardly facing V-shaped bight portions, prong type terminals carried by the other part engageable in said bight portions, and means resiliently holding said two parts for limited longitudinal movement and unlimited rotational movement relative to each other,

2. A transducer including a multipart housing, one of said parts including a cylindrical chamber defining part, a transducer element mounted therein, another one of said parts including a manually graspable knoblike front end part defining a front closure for said chamber, a further one of said parts including a rear end closure cap, contact means mounted in the end cap, and means rotatably supporting said end cap and including terminals engageable by said contacts.

3. A transducer including a multipart housing, one of said parts including a chamber defining part, a transducer element mounted therein, another one of said parts including a manually graspable knoblike front end part, a further one of said parts including an end cap, said further part including a counterbore and contacts in open communication with said counterbore, and a prong type terminal carrying part mounted in said counterbore having prong type terminals rotatably disposed relative to said contacts.

4-. A transducer including a multipart housing, one of said parts including an open ended chambcr defining part, a twist type transducer element mounted therein having a stylus chuck at its outer end, another of said parts including a manually graspable knoblike front end part closing the open end of said chamber and a resilient abutment between said front end part and chuck.

5. A transducer, including in combination, a chamber defining par-t having a transducer element chamber at its front end and a counterbore at its rear end, a transducer element mounted in said chamber, a manually graspable knoblike front end closure fixedly secured to the front end of said chamber, abutment means between said front end closure and the transducer element, a rear end closure for said chamber having a reduced front end portion extending into and fixedly secured to the counterbore in said chamber defining part, said closure having a counterbore at its rear end and a central aperture therethrough, supporting means for said rear end closure portion having a central aperture therethrough, means rotatably securing the rear end closure and supporting memher for rotation relative to each other including a central support extending through said apertures and spring means permitting relative axial movement between the two, contact means in electrical contact with the transducer element and mounted in said rear end closure member and having portions extending through the end closure member, and pnong type terminals secured to said supporting means and engageable with said contact means in difierent relative positions of said supporting means and housing.

6, A transducer comprising a housing member defining a chamber within which is mounted a transducing element, said member also defining a counterbore, first contact means connected to said transducing element and in open communication with the interior of said counterbore, second contact means positioned in said counterliore and movable into engagement with said first contact means, and means connecting said second contact means with said housing member for rotary and trans latory movement relative to each other.

7. A transducer comprising an elongated housing member defining a chamber within which is mounted a transducer element extending substantially along the longitudinal axis of said member, first contact means mounted on said housing member and connected to said transducer element, second contact means movably mounted on said elongated housing member and movable into engagement with said first contact means, and means connecting said second contact means with said housing member for rotary movement about said axis and for translatory movement substantially along said axis.

8, A multiple stylus transducer comprising a first transducer part carrying said styli, a second transducer part adapted to be held in a fixed position, means mounting said first part for unlimited rotation relative U0 said second part, and combined contact and positioning means carried on said first and second parts spaced one hundred eighty degrees from each other and movable into engagement with each other both to locate said first and second parts at angularly spaced predetermined positions relative to each other and to complete electrical connections between said first and second parts.

References Cited in the file of this patent UNITED STATES PATENTS 252,641 Anders Jan. 24, 1882 1,760,647 Hopkins May 27, 1930 1,822,932 Loughridge Sept. 15, 1931 2,454,667 Morse Nov. 23, 1948 2,548,082 Tourtellot Apr, 10, 1951 2,553,492 Weil May 15, 1951 2,570,578 Martin Oct. 9, 1951 

